This invention relates generally to data processing and, more particularly, to a method and apparatus for analyzing the performance of a data processing system.
A portion of the disclosure of this patent document contains material which is subject to copyright protection. The copyright owner has no objection to the facsimile reproduction by anyone of the patent document or the patent disclosure as it appears in the U.S. Patent and Trademark Office patent file or records, but otherwise reserves all copyright rights whatsoever. The following notice applies to the software and data as described below and in the drawings hereto: Copyright (copyright) 1997-1999, Microsoft Corporation, All Rights Reserved.
In the field of data processing it is a well known problem that software developers usually require a period of time to identify and resolve functional and performance issues in the code they have written or integrated. There can be many reasons for such issues, including the basic system and software architecture; non-optimized and/or flawed coding; the choice of, utilization of, and contention for system resources; timing and synchronization; system loading; and so forth.
Particularly in the area of distributed computer networks, it can be extremely difficult for software developers to observe and isolate undesirable system performance and behavior. A distributed computer network is defined herein to mean, at a minimum, a data processing system that utilizes more than one software application simultaneously or that comprises more than one processor.
For example, a single box or machine which is running two or more processes, such as a data base application and a spreadsheet application simultaneously, fulfills this definition. Also, a single article such as a hand-held computer may comprise more than one microprocessor and thus fulfills the definition.
More commonly, however, distributed computer networks may comprise two or more physical boxes or machines, often hundreds or even millions (in the case of the Internet). A software developer trying to monitor and analyze the operation and behavior of such complex computer networks is faced with a very daunting task.
For example, a developer may be writing or have written a server component that performs credit checks. This software component is used in a larger application that performs order entry processing. There are several other server components in the system (such as inventory verification, order validation, etc.) some of which run on the same server and some which run on a separate server (where the inventory database resides). To complicate matters, each component could reside on a computer system in a different state or country. If the application is not performing or behaving well, the developer needs to figure out if there is a performance or behavioral problem and, if so, be able to determine exactly where the trouble spots are.
In the prior art the developer had to modify his or her application, by writing trace statements in the code and having the application write to a log file what was going on at different places in the network. Then all of the log files would need to be collected, merged, and sorted. The developer would then have to sift through the data in a time-intensive fashion and attempt to determine the performance problem.
There are several serious deficiencies with the prior approach.
One problem is that only instrumented code can be analyzed. That means source code must be modified, recompiled, and re-deployed. This is a serious issue with the widespread use of operating system services and component technology in today""s applications. Users are typically unable to recompile operating system and third party components, because they do not have physical or legal access to the source code. When they do have access to the source code, they are still unable to instrument them effectively, because they do not understand the component source code that they do have.
Another problem is that the modifications to code made by developers in an attempt to analyze its performance themselves adversely impact the application""s performance. Further, the development of a highly efficient mechanism for recording the application data is non-trivial. Typical implementations involve writing data to disk. Even if the input/output (I/O) is buffered asynchronously, it can have an adverse impact on the application being monitored (e.g. masking actual application I/O).
A further problem is that understanding control flow during transitions is very hard. Typically, in a large distributed application, transitions to separate processes, or to processes running on separate machines, are common, and may happen simultaneously. Since events have to be manually merged by the developer, it is typically hard to determine which suspension in one process corresponds to resumption in another.
An additional problem is that frequently there are a large number of application areas that might need to be analyzed; however, not all of them may need to be analyzed at the same time. Developers who manually instrument their code must incorporate a selection technology to enable different portions to be analyzed. Otherwise, the load of all of the instrumentation has a severe impact on the analysis. This also requires a complex mechanism for developers to specify which information to collect on which machine.
Yet another problem is that for distributed applications, logs from multiple machines (and often multiple logs per machine) must be merged and sorted. Without synchronized clocks, this task is very difficult. As well, if the log files are in different formats (which is likely if they are from different developers or companies), then the data must be translated into common formats.
The result of all the effort described in this section is a very long list of analysis data. Manually analyzing and isolating performance problems from this amount of data is a very complex and difficult task.
One further problem with known performance analysis of data processing systems is that very often such analysis provides opportunities for breaching the data security of such systems.
There exists known performance monitoring software in various forms. Among them is software known as PerfMon software, which is commercially available from Microsoft Corporation. PerfMon software is a utility which, among other things, can provide an indication of the utilization of the computer""s central processor unit (CPU) and memory unit. PerfMon software operates by sampling. That is, it tracks continuous data by monitoring a machine and looking at its behavior. It can track the free space on a disk, monitor network usage, and so on, but it cannot gather event-based information, such as what function was most recently started.
There also exist known tools called profilers. These look at a single executing software application and try to understand its performance. They do this either by monitoring the program (in a similar way to PerfMon software), or else they hook into the program they are monitoring and generate xe2x80x9ceventsxe2x80x9d each time a program subcomponent (function) commences or completes. Profilers typically have a massive impact on the performance and behavior of an application, because they are intrusive, and they typically require special compiler support. Their data is so detailed that it is normally impractical to use them, particularly in a distributed computing environment such as the one described above.
The Windows NT(copyright) PerfMon utility, commercially available from Microsoft Corporation, provides an extensible architecture for the collection and display of arbitrary application and system counters and metrics. Windows NT provides base counters for the system for the purpose of monitoring CPU and memory utilization. It also provides counters for networks, disks, devices, processes, and so forth. Most system objects export counters. Many applications available from Microsoft Corporation (such as MTS and SQL Server) and other suppliers provide additional counters.
Therefore, there is a substantial need to provide software developers with automated tools for efficiently analyzing the performance, function, and behavior of their applications.
There is also a substantial need to provide such developers with tools for analyzing the performance, function, and behavior of their applications, either while the applications are executing or post mortem, and without significantly affecting the performance or data security characteristics of the applications
In addition, there is a substantial need, in a commercial environment, to provide Application Program Interfaces (APIs) to such tools.
The above-mentioned shortcomings, disadvantages and problems are addressed by the present invention, which will be understood by reading and studying the Detailed Description of the Invention. However, a brief summary of the invention will first be provided.
The present invention includes a number of different aspects for analyzing the performance of a data processing system. For the purposes of describing this invention, the term xe2x80x9cperformancexe2x80x9d is intended to include within its meaning not only the operational performance, but also the function, structure, operation, and behavior of a data processing system.
While the invention has utility in analyzing the performance of a software application that is executing on a distributed data processing system, its utility is not limited to such, and it has utility in analyzing the performance of computer hardware, computer software of all types including data structures, and a wide spectrum of data processing systems comprising both computer hardware and computer software.
Insofar as the overall architecture and operation of the present invention is concerned, each machine where a portion of a distributed software application executes has at least one local event concentrator (LEC). In addition, there is at least one in-process event creator (IEC) and at least one dynamic event creator (DEC) per machine. The function of an IEC is to monitor the executing process for particular situations that occur which the developer wants to be monitored and to create an xe2x80x9ceventxe2x80x9d that can be captured and later analyzed. The function of a DEC is similar to that of an IEC, but it monitors some aspect of the system operation that the developer wants to be monitored on a periodic or time basis and creates an xe2x80x9ceventxe2x80x9d that can also be captured and later analyzed.
The developer can specify by means of a xe2x80x9cfilterxe2x80x9d what to look for in the system under examination. This narrows the scope of the search to what is of interest to the developer and reduces the burden on the performance monitoring system.
When the IEC and DEC create events, they send them to the LEC, which collects them and temporarily stores them, either until the developer requests them or a developer-defined condition or xe2x80x9ctriggerxe2x80x9d occurs, whereupon the LEC sends the events to the developer""s control station. The control station analyzes the events and visually displays the results of the analysis to the developer in a multi-windowed, time-synchronized display.
In order to prevent the collection of information from adversely affecting the performance of the system, the IEC and DEC are only active when they are carrying out the developer""s orders to monitor certain things. Otherwise they are dormant and do not affect the performance. When an IEC is activated and is monitoring process execution for particular situations, it creates a stream of events during xe2x80x9cnormalxe2x80x9d execution and sends them to the LEC. However, the LEC doesn""t send them through the network to the developer""s control station until they are needed.
In another aspect of the invention, a data design structure allows two communicating entities to describe their interactions and inter-relationships despite knowing almost nothing about each other. The data design structure includes pre-defined event fields and custom fields, and it breaks up the application into a series of black boxes and maps out the entities of the network and their inter-relationships for displaying to the developer an animated model of the application as it is executing, either in real time or xe2x80x9cpost mortemxe2x80x9d.
In another aspect, the invention provides for user-defined triggers which cause the performance analysis software to passively buffer events until a malfunction occurs, then dump the buffered data and analyze it. This allows low-impact monitoring, since no information is stored until something of interest happens.
In another aspect, the invention comprises filter reduction features with which the developer can specify exactly what information within the network is of interest. Filter reduction is used to narrow the scope of the filter to extract only the information of interest and hence reduce the performance impact of monitoring.
In another aspect, the invention comprises filter combination features with which different users can specify individual filters that can be combined. The LEC can be multi-threaded and combine filters submitted by multiple users.
In another aspect, the invention comprises a filter user interface which is a graphical representation of the machines, entities, and events making up the network. The user can easily pick those of interest, using displayed lists and Boolean operator tabs, or can simply write an order in text format which is converted to the appropriate filter.
In another aspect, the invention comprises APIs for registration, in-process event creators, dynamic event creators, and other functions implementing the various aspects of the invention.
In another aspect, the invention provides for the automatic generation of an animated application model of the process under examination. A dynamic diagram of the application is automatically displayed as the various constituents interact. A video cassette recorder (VCR) paradigm is used to xe2x80x9cplay, replay, stop, pause, change speed, and reversexe2x80x9d the display, to enable the user to see what""s happening as the application executes.
In another aspect, the invention provides for automatic, synchronized display of all performance analysis data. A number of user-customized, synchronized display windows show the constituent parts of the application execution and the corresponding performance characteristics, in both Gantt chart and graphical modes, either in real-time or post-mortem. A timeline window displays a visual representation of the timing of all related events. A summary window displays a distillation of the system performance during a user-selected time slice.
In another aspect, the invention provides suitable data security mechanisms throughout the network being monitored. Discretionary access is applied to the collection of data from a specific machine.
The present invention describes systems, clients, servers, methods, and computer-readable media of varying scope. In addition to the aspects and advantages of the present invention described in this summary, further aspects and advantages of the invention will become apparent by reference to the drawings and by reading the Detailed Description that follows.